This invention relates to a mechanical component comprising anti-static material. The mechanical component is applied to equipment such as a copying machine, a facsimile machine, or an electrostatic plotter. Such equipment makes copies or draws charts using electrostatic adsorption.
Since mechanical components such as gears and pulleys are generally made of conductive metal, they require no static-prevention measures.
On the other hand, since drive belts, non-driven belts, paper-feed rollers, and the light carriages of a copying machine require some elasticity, they are made of synthetic resins such as silicon rubber or hard rubber. When mechanical components such as the drive belts and the paper-feed rollers are made from an insulating material like synthetic resin, friction generates static electricity on the surfaces of the mechanical components. Consequently, the related-art mechanical component is made of synthetic resin with conductive fillers such as carbon black or metallic particles mixed in so that the mechanical component does not become charged with static electricity.
However, a mechanical component made of synthetic resin containing conductive fillers will not have sufficient conductivity and will develop problems.
When carbon black is mixed into synthetic resin, the electric resistivity of the synthetic resin is reduced, but its mechanical strength is also reduced. The amount of carbon black added must be carefully regulated. When the maximum amount of carbon black is mixed into the synthetic resin, it is difficult to obtain the optimum resistivity for the synthetic resin. The optimum resistivity for preventing synthetic resin from being charged with static electricity is between 10.sup.5 and 10.sup.9 ohm.cm. As the amount of carbon black increases, electric resistivity rapidly decreases from about 10.sup.10 ohm.cm to about 10.sup.2 ohm cm. Thus, it is difficult to optimally adjust the electric resistivity when mixing carbon black into synthetic resin.
The related-art conductive mechanical component, which is made of synthetic resin mixed with carbon black, has little static-prevention effect and may allow malfunctions of equipment that uses electrostatic adsorption. For example, when copying paper that has electrostatically adsorbed toner is fed by a paper-feed roller, either static electricity on the paper-feed roller strips the toner from the paper, or the paper sticks to the paper-feed roller.
Alternatively, the mechanical component can consist of synthetic resin with metallic particles mixed in. However, metallic particles, which differ from synthetic resin in specific gravity, cannot be distributed uniformly in the synthetic resin. For example, when a drive belt is made of synthetic resin mixed with metallic particles, the electric resistivity of the driven belt is inconsistent, and the drive belt remains partially charged with static electricity.